Office of Compensation Analysis and Support Document Number: OCAS-PER-003

Program Evaluation Report Effective Date: (1/28/2005)

Revision No. 0

Evaluation of the Effect of Adding Ingestion Intakes to Bethlehem 

Steel Cases 

Page 1 of 3 

Approval:__Signature on file_____ Date: ____________ 

 J.W. Neton, Associate Director for Science 

Supersedes: None 

RECORD OF ISSUE/REVISIONS 

ISSUE 

AUTHORIZATION 

DATE 

1/28/2005

EFFECTIVE 

DATE 

1/28/2005 

REV. NO. 

0 

DESCRIPTION 

New document to evaluation the effect of adding 

ingestion intakes to previously finished claims 

from Bethlehem Steel 

1.0 Description

On 3/31/2003 NIOSH completed a Technical Basis Document assessing exposures to 

uranium at the Bethlehem Steel Corporation facility. The original document did not 

assess intakes of uranium through an ingestion route. The document has since been 

revised on 6/29/2004 to include this exposure pathway. The purpose of this PER is to 

evaluate the effect on this additional intake on previously completed claims. 

2.0 Evaluation

Intakes 

The Bethlehem Steel Technical Basis Document (TBD) estimated annual exposures to 

uranium and prescribed using the same exposure for each year of employment. Intakes 

were originally determined for inhalation only, however, since that time, additional 

intakes via the ingestion pathway have been added. The additional intakes where based 

on the quantity of uranium estimated to be in the air. Therefore, the increased intake of 

uranium is a fixed percentage of the previously determined inhalation intake. Individual 

organ doses will also increase by a set percentage, however, this increase will vary for 

each organ. 

Dose Evaluation 

Since the exposure was estimated at a constant rate, the increased dose should be 

proportional to the original dose regardless of the exposure time. For this evaluation, 

organ doses were calculated for a hypothetical employee that worked at Bethlehem Steel 

during the entire contract period (1949 to 1952). Annual doses were calculated for 

various organs starting in 1949 and ending in 2002. These doses were compared with the 
Office of Compensation Analysis and Support

Document Number: OCAS-PER-003 Program Evaluation Report 

Effective Date: (128/2005) Revision No. 0 Page 2 of 3 

original (inhalation only) doses to determine the percentage increase in dose for each 

organ. 

The f1 value is the fraction of material absorbed into the body from the GI tract. The f1, 

value for this evaluation was chosen to be consistent with the lung absorption type used 

in the Bethlehem Steel TBD. The TBD uses the most claimant favorable of the credible 

solubility types. This results in the use of type S material for respiratory tract doses and 

type M for all other organs. 

The highest increase in dose occurred in the first year of exposure for all organs other 

than the respiratory tract. The difference in respiratory tract dose continued to increase 

through 2002, the largest difference being a 0.62% increase in the ET2 compartment. 

The increase was higher for all other organs in all years of exposure. The majority of 

organs had an increased dose of approximately 0.94% in the first year and quickly 

(within a few years) decreased to a 0.74% increase. The only remaining tissues with 

significantly different doses are the tissues associated with the GI tract. The largest 

difference in dose was found in the lower large intestine (LLI) tissue. The largest 

increase in dose to the LLI was 5.62%, occurred in the first year. Other tissues of the GI 

tract also exhibited the maximum increase in the first year. 

Probability of Causation 

The dose estimate is used to determine the Excess Relative Risk (ERR). The probability 

of Causation (POC) is determined directly from the ERR. The relationship is: 

POC = ERR/(1+ERR)*100% 

From this equation it can be seen that an ERR of 1 is required to yield a POC of 50%. 

For a given scenario of time since exposure, age at diagnosis, type of cancer, type of 

radiation, etc., the ERR varies essentially linearly with the dose. Therefore, a 5.62% 

increase would be sufficient to raise the ERR from 0.947 to 1.0. An ERR of 0.947 would 

produce a POC of 48.6%. For non-GI tract cancers, an increase in dose of 0.94% would 

be sufficient to raise the ERR from 0.990 to 1.0. An ERR of 0.990 corresponds to a POC 

of 49.7%. 

3.0 Results of Evaluation

A search of the existing claims in December 2004 indicated that 7 of the Bethlehem Steel 

claims submitted to the Department of Labor had a POC below between 40% and 50%. 

One of these claims included ingestion dose in the original version. Five of the 

remaining six did not exceed the POC threshold above that may cause the claim to 

exceed a POC of 50%. One however did exceed that threshold. However, the threshold 

is conservative in that it assumed the largest annual increase in dose occurred every year. 

All six claims where however, re-evaluated using the current version of the TBD. The 
Office of Compensation Analysis and Support

Document Number: OCAS-PER-003 Program Evaluation Report 

Effective Date: (128/2005) Revision No. 0 Page 3 of 3 

new version of the TBD included changes to the medical x-ray doses as a result of 

additional information. Once the new dose values were entered, the POC calculation was 

run 30 times with a different random seed value each time. This was done in order to 

produce a more precise POC by minimizing minor fluctuations attributable to the 

computation rather than the actual uncertainty in the POC. The average of the 30 runs is 

reported in the table below. 

Table 1 

Claim Cancer type Original POC New POC 

A Chronic Myelocytic 

Leukemia 44.90% 43.72% 

B Kidney 46.36% 45.72% 

C Rectum/ Kidney 49.42% combined 49.11% combined 

D Testis 47.53% 46.37% 

E Chronic & Acute 

Myelomonocytic 

Leukemia

48.32% combined 46.53% combined 

F Kidney 49.27% 47.11% 

As a result of this evaluation, none of the six exceeded a POC of 50%. The reduction in 

the POC values can be attributed to the change in the x-ray dose estimate for these 

claims. 

4.0 Summary

As a result of adding ingestion intakes, the POC of none of the previously completed 

Bethlehem Steel claims would increase to greater than 50%. 

5.0 References

1. ORAU Team (2004) Technical Basis Document: Basis for Development of an 

Exposure Matrix for Bethlehem Steel Corporation, ORAUT-TKBS-0001 Rev 01.